The invention relates to interposer assemblies used for forming electrical connections between spaced contact pads on circuit members.
Interposer assemblies form electrical connections between densely spaced contact pads on adjacent parallel circuit members. An interposer assembly includes an interposer mounted in a frame. The interposer is a circuit device that includes a flat plate holding a number of contact members in a predetermined pattern. The frame positions the interposer between the circuit members with contact members aligned with opposite pairs of contact pads. The circuit members are pressed against the interposer and sandwich the interposer plate between them. The contact members compress between pairs of contact pads and interconnect the circuit members to form an electronics package.
Interposer assemblies are used wherever dense connections are required in an electronics package to transmit electrical signals, including data, between circuit members. The assemblies are particularly well suited for electronic packages used in electronic devices such as cellular telephones, portable digital assistants, notebook computers, control circuits and the like, and enable a reduction in the size and weight of such devices.
Electronic packages are becoming smaller in size and yet are providing ever-increasing levels of performance. Circuit members have more contact pads packed into less space and operate at faster speeds. Despite increases in contact density and operating speeds, interposer assemblies in high-performance electronic packages must make highly reliable and dependable electrical connections that maintain signal integrity between circuit members
Increased contact density and operating speeds, however, cause signal integrity to become sensitive to electromagnetic interference or xe2x80x9cEMIxe2x80x9d. EMI is generated by circuit devices such as microprocessors, and may affect electrical signals in other circuit devices or other electronic packages in an electronic device.
As the performance of circuit members interconnected by interposer assemblies increases, it becomes desirable to shield interposer assemblies from EMI to maintain reliable signal integrity. EMI shields are known that shield circuit devices from EMI emitted by other circuit devices, and block emission of EMI generated by the circuit device itself. These shields, however, are not designed for use with interposer assemblies.
One known interposer assembly has a number of EMI shields that each individually shields a contact member in the plate. Shielding individual contact members is complex and expensive, and is not feasible for many types of interposer assemblies.
Thus, there is a need for an improved EMI-shielded interposer assembly for interconnecting high-performance circuit members of an electronics package. The shielded interposer assembly should be easily manufactured and be usable with different types of interposer assemblies.
The invention is an improved frame for use in an interposer assembly. The frame includes an EMI shield that shields the interposer from EMI. The improved frame is easily manufactured and is usable with many types of interposer assemblies. As an added benefit the improved frame of the present invention is readily adaptable to hold other electronic devices in addition to interposers.
An improved EMI-shielded frame for holding an interposer or other circuit in accordance with the present invention includes a socket for holding the circuit and an EMI shield assembly at least partially surrounding the socket. The socket includes a wall surrounding a central opening extending through the socket for receiving the circuit device. The wall includes an inner surface facing the opening, an outer surface defining the outer perimeter of the wall, and top and bottom surfaces.
The shield assembly faces the outer and bottom wall surfaces and includes an EMI shield facing the outer surface of the socket and at least one contact arm extending from the shield and electrically or thermally connected to the shield. Each contact arm extends from below the bottom wall surface inwardly beyond the inner wall surface to a free end, with a contact surface on the free end to face one of the circuit members. The contact surface engages the one circuit member when the circuit device is sandwiched between the circuit members and electrically or thermally interconnect the one circuit member with the EMI shield.
In a preferred embodiment the circuit device is an interposer having a flat plate and a number of contacts in the plate. The plate has top and bottom sides separated by the thickness of the plate. The interposer contacts have opposed contact noses normally separated by a distance greater than the thickness of the plate.
The shield assembly includes a number of upwardly bent contact arms that have contact noses spaced above the interposer plate and a number of downwardly bent contact arms that have contact noses spaced below the interposer plate. When the interposer is sandwiched between the circuit members, one circuit member engages the contact noses of the upwardly bent contact arms and the other circuit member engages the contact noses of the downwardly bent contact arms. The contact arms electrically or thermally interconnect both circuit members with the EMI shield and may, in some applications, interconnect the shield with the grounds of the circuit members.
In other embodiments one of the circuit members is a heat sink. The contact arms conduct heat from the EMI shield to the heat sink. In yet other embodiments the circuit device is an active device that generates EMI. The EMI shield reduces EMI transmissions from the active device to other electronic devices while interconnecting one or both circuit members to the EMI shield.
The EMI-shielded frame of the present invention has a number of advantages. The EMI shield surrounds and shields the interposer plate and interposer contacts without shielding individual interposer contacts. The contact arms can electrically connect or tie in the EMI shield to the grounds of the circuit members, which is advantageous in many applications. The shield assembly may be manufactured from sheet metal and can be made of individual members that are easily mounted to the frame. The frame is readily adaptable for use in different types of interposer assemblies or other types of electronic packages.
Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings illustrating the invention, of which there are six sheets of drawings of five embodiments.